INST-9 · Institution/affiliation as a first-class field

> Item derived from the fact-checking cycle analysis (**2026-07-03, v2**). New item (companion proposal **ENG-6**).

### Finding (evidence)
Today only the sparse `nameSpace` tag exists; institutional adoption and per-hub coverage aren't queryable from platform data.

### Action
Promote institution/affiliation to a structured, first-class field on the user/task — **not** derived from namespace.

### Impact
Institutional adoption and per-hub coverage become reportable directly from platform data.

---
- **Priority:** 🟡 Medium · **Effort:** M
- **Epic:** #2489

No files or tests are named. Start by reading epic #2489 and companion proposal ENG-6, then locate the user and task data entry points that expose the existing nameSpace tag. Done means institution or affiliation is stored as a distinct structured field and can support direct adoption and per-hub coverage reporting.

Scritto dal modello di indicizzazione a partire dal testo della issue.